1. Field of the Invention
The present invention relates to heat sinks and more particularly, to a combination heat sink formed of a stack of radiation fins. Each radiation fin comprises a plurality of retaining flanges symmetrically disposed at two opposite lateral sides in such a manner that the radiation fins are fastened together in a stack by means of forcing the retaining flanges of one radiation fin into engagement with the retaining flanges of another radiation fin.
2. Description of the Related Art
Following fast development of modern technology, advanced desktop and notebook computers of relatively stronger computing function and higher operating speed are continuously developed. However, the internal CPU of a high-speed computer generates a relatively higher amount of heat. During the operation of a high-speed computer, heat must be quickly carried away from the CPU, avoiding malfunctioning or failure of the CPU. In order to effectively remove heat from the CPU of a computer, a heat sink may be used with an electric fan. During operation, the heat transfer bottom block of the heat sink absorbs heat energy from the CPU and transfers absorbed heat energy to the radiation fins, and at the same time the electric fan causes currents of air toward the radiation fins of the heat sink, carrying heat energy away from the radiation fins to the outside open air. To enhance the heat dissipation efficiency, the number of the radiation fins and the speed of revolution of the electric fan may be increased. However, the thickness of the radiation fins must be reduced so that the number of the radiation fins can be increased without changing the dimension of the heat sink. According to conventional heat sink fabrication methods, radiation fins are bonded to a heat transfer bottom block by welding. It is difficult to weld a big number of thin radiation fins to the limited surface area of a heat transfer bottom block. A small welding error may result in improper positioning of radiation fins. To eliminate this problem, combination heat sinks are developed.
FIGS. 7 and 8 show a prior art design of combination heat sink. According to this design, the combination heat sink A is formed by fastening a number of radiation fins A1 in a stack. Each radiation fin A1 has one side terminating in a coupling flange A11. The coupling flange A11 has a front protrusion A111 and a back recess A112. By means of press-fitting the front protrusion A111 of the coupling flange A11 of one radiation fin A1 into the back recess A112 of the coupling flange A11 of another radiation fin A1, a predetermined number of the radiation fins A1 are fastened together in a stack. According to this design, the connection between each two adjacent radiation fins A1 is not highly stable. The engagement between the front protrusion A111 of one radiation fin A1 and the back recess A112 of another radiation fin A1 prohibits the two radiation fins A1 from movement relative to each other in vertical direction, however it cannot prohibit the two radiation fins A1 from relative movement in transverse direction. During installation of the aforesaid prior art design of combination heat sink A, the radiation fins A1 may vibrate or move from one another out of position, lowering the performance.
Therefore, it is desirable to provide a combination heat sink that eliminates the aforesaid problems.